Howard, just my two penn'orth, but A7 drums are tragically thin to begin with and I would only skim them if the surface is very poor. With a little bedding-in the lining should soon conform to the surface if it is round and only scored.
After fettling, my linings are just 4mm thick so accord with others. Regarding woven material be careful as I have a box of brand new linings, a woven material but but made by Raybestos and almost certainly containing asbestos. My father died of asbestos cancer so I’m a bit paranoiac.
Chris, the drums are Girling so have more meat than Austin ones. I also intend “a light skim” Here’s a pic showing the scoring!
16-07-2020, 11:31 PM (This post was last modified: 17-07-2020, 03:20 AM by Tony Press.)
One of our members has apparently made a tool to round the finished linings (bonded linings as used here for some 40 years) on alloy shoes presumably with the cams at rest.
As noted, with the Austin 7 non self centering shoes this has caused some controversy claiming the linings won't conform to the drum when applied.
I would have thought that the linings would quickly wear to suit - although this may mean that the 'rounding' isn't necessary anyway.
Hi Tony
It is shoes contoured off the vehicle which are questionable, Shoe bearing points have often been filed to equalise so should be kept in position. Radiussing from the brake drum on the car is the ideal. Most old cars now receive so little use bedding in on the road takes too long.
Having done a little over 100 miles since the brake reline, the brakes appeared to be getting worse as the linings bedded in rather than better. having descended a long hill yesterday, i discovered that the rear brakes were warm and the fronts were not. So, I gave my great grandson Leon his first lesson in maintaining a Seven by getting him to assist me in removing the brake drums and resetting the balance between the front and rear axles. The linings are bedding in quite nicely, but, as Bob Culver has pointed out, this is likely to take more miles than I have so far covered, as it appears that we have only about half the total area with a shine on it.
Having an assistant makes setting up the balance makes the job much easier and the brakes are now somewhat sharper. Just as well, as we are due to drive up to Anglesey tomorrow so that Leon and I can see my grandson and his family and to allow Leon to have some time with his cousins.
I have already initiated him into the arcane mysteries of checking oil and water, priming the carburettor and starting the car from cold!
Even with semi girlig a degree of front lead for light braking is desirable. If new shoes chance to bear heavily on the leading edge, may not improve as bed in. Main adjustment at the cable pivot. Opinions differ about the directon of the front cotters but applied the ball should lie under the kingpin
I have a 50 year old box of Ferodo GG/7 sold as for a Seven. .15 thick. But on my car with standard or not much oversisze drums the adj was way out long before the rivets rubbed